Then it's incumbent upon me to show that Tom Knowlton doesn't know WTF he's talking about, I guess.

The 13th SS didn't come into existence until 1943, and then was training in France until becoming operational and deploying back to Bosnia in February of 1944. source

Given that the Germans started rounding up and either murdering or deporting Yugoslavia's Jews (~80k) immediately upon occupying the country in 1941, and had liquidated or deported Serbia's 16k Jewish population by 1942 (20% of Yugoslavia's total), the notion that a unit which didn't commence operations until February of 1944 could have been responsible for the deaths of 90% of Yugoslavia's Jewry between the various antipartisan operations that it took part in during its year or so of operations in Yugoslavia is mathematically impossible, to say nothing of being patently absurd.